1. Field of the Invention
This invention relates to a cassette tape magnetic recording/reproducing apparatus, such as a tape recorder, wherein the magnetic tape accommodated within a tape cassette attached at a tape cassette attachment position within the main body of the recording/reproducing apparatus is extracted by a loading mechanism or unit and loaded onto a predetermined tape running route or path.
More particularly, the present invention relates to a cassette tape magnetic recording/reproducing apparatus wherein the loading operation of the magnetic tape is enabled on the condition that it is sensed that a cassette holder for attaching the tape cassette at the tape cassette attachment position and that the tape cassette is attached at the tape cassette attachment position, in such a manner that a positive tape loading operation is assured and the magnetic tape as well as various operating units within the main body of the apparatus are protected from possible damage.
2. Description of the Prior Art
There is proposed and actually employed a cassette type magnetic recording/reproducing apparatus, such as a rotary magnetic head type audio PCM tape recorder or a video tape recorder, wherein the tape cassette accommodating a magnetic tape is employed as the recording medium and the magnetic tape accommodated within the tape cassette is caused to run as it is wrapped around the tape guide drum of the rotational magnetic head device, and slidability contacted by a rotating magnetic head for recording/reproducing audio or video signals.
The above described cassette type magnetic recording/reproducing apparatus is provided with a cassette holder and a tape cassette transfer member supported for movement between a tape cassette inserting and detachment position and a tape cassette attachment position, and the tape cassette is attached at the tape cassette attachment position by way of the tape cassette transfer member or the cassette holder.
In a cassette type magnetic recording/reproducing apparatus employing a rotating magnetic head device, the magnetic tape taken out from the tape cassette is wrapped around a tape guide drum of the rotating magnetic head device at a predetermined angle for slidingly contacting with the rotating magnetic head. For this reason, the tape running route or path is intricate in profile and in the form of a letter M or a letter U with the magnetic head device as the center. Since the magnetic tape is loaded along an intricate tape route, a loading mechanism including a shifting guide roller is provided in the cassette type magnetic recording/reproducing apparatus. The magnetic tape is taken out of the tape cassette by way of the aforementioned loading mechanism so as to be wrapped around the tape guide drum and automatically loaded onto the tape travel path.
Therefore, in a cassette type magnetic recording/reproducing apparatus in which the magnetic tape is automatically loaded onto the tape travel path through the loading mechanism, it is necessary that the tape cassette be attached positively and accurately at the tape cassette attachment position. The loading mechanism is so constructed and designed that the magnetic tape extending on the front side of the tape cassette can be hooked for extraction by tape guide means, such as shifting guide rollers. Therefore, when the tape cassette is not attached accurately at the predetermined tape cassette attachment position, it may occur that the tape guide means are not engaged with the magnetic tape or are disengaged therefrom during extraction so that it may become impossible to perform a tape loading operation. Also, when the tape guide means are not engaged accurately with the magnetic tape, the magnetic tape may not be reliably protected from possible damage, while the loading mechanism itself may be destroyed.
In the conventional cassette type magnetic recording/reproducing apparatus, the operation of the loading mechanism is started as soon as it is sensed that the cassette holder has been shifted to the tape cassette attachment position to effect the loading of the magnetic tape, or alternatively, a loading start switch is actuated after the cassette holder has been shifted to the tape cassette attachment position to start loading of the magnetic tape. Thus, in the conventional cassette type magnetic recording/reproducing apparatus, the loading operation is started without checking to see that the cassette holder has been correctly shifted to the tape cassette attachment position and that the tape cassette attachment position and that the tape cassette has been correctly attached to the tape cassette attachment position. Thus there is a risk that the loading mechanism is actuated when the cassette holder has been shifted to the tape cassette attachment position, even though the tape cassette is not attached correctly at the tape cassette attachment position. Therefore it may occur that the magnetic tape loading may cause damage to the magnetic tape and to operating units including the tape loading mechanism.
In addition, in the above described cassette type magnetic recording/reproducing apparatus employing the rotating magnetic head device, the magnetic tape is extracted out of the tape cassette and wrapped around the rotating magnetic head device spaced apart from the tape cassette along the tape travel path or route. Supposing that the tape cassette ejecting operation is performed during the loading operation in which the magnetic tape is extracted or pulled out onto the tape route or the unloading operation in which the magnetic tape is pulled back into the tape cassette or under the loading condition in which the magnetic tape is wrapped around the rotating magnetic head device, the tape cassette ejecting operation is performed while the magnetic tape is still extended on the tape route without being accommodated within the tape cassette. The magnetic tape is pulled out in such case as it is entwined about tape guide means such as tape guide rollers so that the tape may be broken or otherwise damaged. In addition to the magnetic tape being damaged, the mechanical units including the tape running mechanism or the loading mechanism may be damaged by the magnetic tape remaining on the tape route.